Traditionally, visually impaired persons have commonly experienced limited mobility due to hazardous obstacles, sudden and/or unexpected changes in the underlying walking surface, (i.e. stairways, hills, pot holes, etc), as well as a host of other potentially dangerous or disruptive situations (e.g. passing vehicles, pets and other persons) they may encounter. Individuals having visual impairments have often resorted to the use of a cane or service dog. However, both of these aids have serious limitations and can be particularly unreliable at detecting sudden or unexpected obstacles or other potential dangers. They also fail to provide the user with locational information or navigational guidance.
Recently, electronic systems have been developed for warning visually impaired persons of approaching obstacles and impediments. However, most of these are limited to simply notifying the user that a potential obstacle is approaching. Products have also been introduced that attempt to advise the user of the type of object he or she is approaching. In one of these, an electronic camera transforms a digital image of the approaching object into an electrical signal that stimulates the user's tongue. Unfortunately, it takes an inordinate amount of time for the user to decipher the electrical stimulus from the tongue and associate it with an image of the approaching object. An alternative method involves implanting an image stimulating electronic component in the user's retinas. This technique is unproven and, in any event, is prohibitively expensive for most potential users.